Gas monitoring apparatus and system for artificial ventilation

Abstract

A gas monitoring system for artificial ventilation includes: a sensor that is configured to produce a signal corresponding to a concentration of a predetermined gas in a portion which is in a respiratory circuit of an artificial ventilator, and through which both an inspiratory gas and an expiratory gas pass; a displaying apparatus that is communicable with the sensor; a processor; and a memory that is configured to store a command which is readable by the processor. When, during high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, the processor is to configured to calculate a measurement value of the concentration based on the signal, and is configured to display at least one of a waveform corresponding to the signal and the measurement value on the displaying apparatus.

What is claimed is: 
     
       1. A gas monitoring system for artificial ventilation, the gas monitoring system comprising:
 a sensor that is configured to produce a signal corresponding to a concentration of a predetermined gas in a tube in a respiratory circuit of an artificial ventilator, wherein an inspiratory gas and an expiratory gas pass both pass through the tube, the inspiratory gas passing in a first direction and the expiratory gas passing in a second direction opposite to the first direction; 
 a displaying apparatus that is communicable with the sensor; 
 a processor; and 
 a memory that is configured to store a command which is readable by the processor, wherein, 
 when, during high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to calculate a measurement value of the concentration based on the signal, 
 the processor is configured to display at least one of a waveform corresponding to the signal and the measurement value on the displaying apparatus, 
 the sensor is configured such that the sensor is located at an ex vivo portion of the tube when the respiratory circuit is connected to a patient for ventilation and the sensor is operated, 
 the processor is configured to extract a high-frequency component having a frequency which is higher than a predetermined value, from the signal, and 
 the processor is configured to determine if the high-frequency oscillatory ventilation satisfies a desired waveform based on the high-frequency component. 
 
     
     
       2. The gas monitoring system according to  claim 1 , wherein,
 when, during the high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to extract a low-frequency component having a frequency which is lower than a predetermined value, from the signal, and 
 the processor is configured to detect spontaneous respiration of the patient to whom the artificial ventilator is connected, based on the low-frequency component. 
 
     
     
       3. The gas monitoring system according to  claim 2 , wherein, in a case where the low-frequency component satisfies a predetermined condition, the processor is configured to produce a signal for causing the artificial ventilator to perform low-frequency ventilation. 
     
     
       4. The gas monitoring system according to  claim 1 , wherein,
 when, during the high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to display a measurement value of the concentration which is obtained after an end of sustained inflation of the lungs, as a feature value. 
 
     
     
       5. The gas monitoring system according to  claim 4 , wherein,
 when, during the high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to display the feature value separately from the measurement value of the concentration. 
 
     
     
       6. The gas monitoring system according to  claim 4 , wherein
 determination that the sustained inflation is performed is conducted by acquiring information indicating that the sustained inflation is performed from the artificial ventilator. 
 
     
     
       7. The gas monitoring system according to  claim 4 , wherein
 determination that the sustained inflation is performed is conducted based on a state where an amplitude of the waveform zero is continued for a predetermined period of time or longer. 
 
     
     
       8. The gas monitoring system according to  claim 4 , wherein
 the processor is configured to calculate the feature value by acquiring a moving average of a plurality of peak values of the waveform contained in a predetermined period of time. 
 
     
     
       9. The gas monitoring system according to  claim 4 , wherein
 the processor is configured to calculate the feature value by acquiring a maximum value of a plurality of peak values of the waveform contained in a predetermined period of time. 
 
     
     
       10. The gas monitoring system according to  claim 1 , wherein
 the processor is configured to calculate the measurement value of the concentration by acquiring a moving average of a plurality of peak values of the signal contained in a predetermined period of time. 
 
     
     
       11. The gas monitoring system according to  claim 1 , wherein
 the processor is configured to calculate the measurement value of the concentration by acquiring a maximum value of a plurality of peak values of the signal contained in a predetermined period of time. 
 
     
     
       12. The gas monitoring system according to  claim 1 , wherein
 the processor is configured to display a frequency value corresponding to a cycle of the extracted high-frequency component on the displaying apparatus. 
 
     
     
       13. The gas monitoring system according to  claim 1 , wherein,
 when, during the high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to extract a low-frequency component having a frequency which is lower than a predetermined value, from the signal, and 
 the processor is configured to calculate a respiration rate based on a cycle of the extracted low-frequency component. 
 
     
     
       14. The gas monitoring system according to  claim 1 , wherein the sensor includes:
 a light emitter that is located so as to emit a light beam toward the ex vivo portion of the tube, and 
 a light detector that is located so as to receive the light beam after passing through the ex vivo portion. 
 
     
     
       15. The gas monitoring system according to  claim 1 , wherein:
 the respiratory circuit includes an inspiratory circuit section, and an expiratory circuit section, one end of the tube being bifurcated into the inspiratory circuit section and the expiratory circuit section, and 
 the sensor is located at the ex vivo portion of the tube. 
 
     
     
       16. The gas monitoring system according to  claim 1 , wherein the sensor includes a light emitter configured so as to emit a light beam toward the tube and a light detector configured so as to produce the signal corresponding to intensity of the received light beam, wherein a response time of the light detector is 55 milliseconds or shorter. 
     
     
       17. A gas monitoring apparatus for artificial ventilation, the gas monitoring apparatus communicable with a sensor that is configured to produce a signal corresponding to a concentration of a predetermined gas in a tube in a respiratory circuit of an artificial ventilator, wherein an inspiratory gas and an expiratory gas both pass through the tube, the inspiratory gas passing in a first direction and the expiratory gas passing in a second direction opposite to the first direction, the gas monitoring apparatus comprising:
 a displaying section; 
 a processor; and 
 a memory that is configured to store a command which is readable by the processor, wherein, 
 when, during high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to calculate a measurement value of the concentration based on the signal, 
 the processor is configured to display at least one of a waveform corresponding to the signal and the measurement value on the displaying section, 
 the sensor is configured such that the sensor is located at an ex vivo portion of the tube when the respiratory circuit is connected to a patient for ventilation and the sensor is operated, 
 the processor is configured to extract a high-frequency component having a frequency which is higher than a predetermined value, from the signal, and 
 the processor is configured to determine if the high-frequency oscillatory ventilation satisfies a desired waveform based on the high-frequency component. 
 
     
     
       18. The gas monitoring apparatus according to  claim 17 , further comprising a notifying section that provides a notification if the processor determines that the high-frequency oscillatory ventilation does not satisfy the desired waveform. 
     
     
       19. The gas monitoring apparatus according to  claim 17 , wherein,
 the processor is configured to display a measurement value of the concentration which is obtained after an end of sustained inflation of the lungs, as a feature value. 
 
     
     
       20. The gas monitoring apparatus according to  claim 17 , wherein
 the processor is configured to calculate the measurement value of the concentration by acquiring a moving average of a plurality of peak values of the signal contained in a predetermined period of time. 
 
     
     
       21. The gas monitoring apparatus according to  claim 17 , wherein the sensor includes:
 a light emitter that is located so as to emit a light beam toward the ex vivo portion of the tube, and 
 a light detector that is located so as to receive the light beam after passing through the ex vivo portion. 
 
     
     
       22. A gas monitoring apparatus for artificial ventilation, the gas monitoring apparatus communicable with a sensor that is configured to produce a signal corresponding to a concentration of a predetermined gas in a tube in a respiratory circuit of an artificial ventilator, wherein an inspiratory gas and an expiratory gas both pass through the tube, the inspiratory gas passing in a first direction and the expiratory gas passing in a second direction opposite to the first direction, the gas monitoring apparatus comprising:
 a displaying section; 
 a processor; and 
 a memory that is configured to store a command which is readable by the processor, wherein, 
 when, during high-frequency oscillatory ventilation performed by the artificial ventilator, the command is executed by the processor, 
 the processor is configured to calculate a measurement value of the concentration based on the signal, 
 the processor is configured to display at least one of a waveform corresponding to the signal and the measurement value on the displaying section, 
 the sensor is configured such that the sensor is located at an ex vivo portion of the tube when the respiratory circuit is connected to a patient for ventilation and the sensor is operated, 
 the processor is configured to extract a low-frequency component having a frequency which is lower than a predetermined value, from the signal, and 
 in a case where the low-frequency component satisfies a predetermined condition, the processor is configured to produce a signal for causing the artificial ventilator to perform low-frequency ventilation. 
 
     
     
       23. The gas monitoring system according to  claim 22 , wherein the processor is configured to detect spontaneous respiration of the patient to whom the artificial ventilator is connected, based on the low-frequency component.